The invention relates to a device and a method for determining the volume of an object moved by an industrial truck.
In piece goods logistics, it is necessary to determine the freight volume and the volume of individual load items, respectively, so as to be able to determine the freight space required as accurately as possible. A known approach, but one that is inaccurate, is to estimate the freight volume of a delivery on the basis of a declared weight by way of an average goods density of the items. Furthermore there are measuring systems of known prior art, which require the object is measured to be stationary and freestanding; however, this leads to disadvantageous delays and interruptions in workflow, since, in logistics terminals or transhipment terminals in particular, the daily volume of freight must be ascertained in short time slots.
A need therefore exists for a measuring device, which enables the determination of the volume of the loaded goods without any interruption or changes to the logistics processes internal to the terminal. Such a volume-measuring device for moving objects is already of known art from EP 2 439 487 B1. For purposes of sensing the contour of loaded goods it is, for example, proposed to deploy four contour sensing sensors designed as laser scanners, which in each case scan the loaded goods that are being moved line-by-line, that is say, layer-by-layer as they pass by, and to image the received light beams on line-form image sensors, so that a view onto the loaded goods is ascertained in the form of strip images sensed one after another.
Such a line-based, or strip-based laser scanning method requires, however, that the individual scanned strip images of the moving loaded goods are reconstituted at the correct distance, i.e. taking into account the movement of the loaded goods in order to obtain an overall external contour of the loaded goods and the means of transport. Thus the sensed data must be laboriously reconstituted while detecting the movement of the loaded goods, a process that is cost-intensive and subject to errors. The reason for this lies in the fact that, depending upon the recording speed of the sensor, each image line per se is slightly delayed, since each pixel, that is to say, each point on the line, is recorded one after another. The distortion differs with varying, or fluctuating speeds of the loaded goods, and is also dependent on the distance of each point from the sensor. At the same speed, points that are nearer move further than points that are further away relative to the sensor. For the reconstitution of a single image the movement of the object must thus be ascertained and calculated. For this purpose a highly accurate odometry sensor is required, by means of which the movement is determined.
A further disadvantage of such a strip-based laser scanning method is the fact that while such laser scanners do enable a comparatively high resolution of a contour of the loaded goods, they are comparatively expensive.
A further device for determining the dimensions of loaded goods that are being moved is of known art from U.S. Pat. No. 7,757,946 B2, which has similar disadvantages to those described above. The patent document U.S. Pat. No. 8,599,303 B2 describes the build of a time-of-flight camera, which can be used for the optical sensing of the dimensions of an object that is being moved on a conveyor belt. Furthermore from U.S. Pat. No. 6,798,528 B1 a system for determining the dimensions of a moving object is of known art, which is used for the measurement of parabolic mirrors. What is disadvantageous here is the comparatively complex build and the difficulty, as a result of the measurement process, of being able to measure irregular objects accurately.
Thus it is an object of the invention to provide an improved device and an improved method for determining the volume of an object that is being moved by means of an industrial truck, with which the disadvantages of the conventional techniques can be avoided. In particular it is the object of the invention to provide a device for determining the volume of an object moved by means of an industrial truck, with which a reliable determination of the volume of the loaded goods that are being moved is made possible, without having to alter existing logistics processes internal to the terminal, or having to interrupt these for purposes of measuring the volume. A further object underlying the invention is to provide a device for purposes of determining the volume of an object moved by an industrial truck, which can be arranged in a cost-saving and space-saving manner in the domain of a loading terminal, in particular in the domain of a loading gate of a logistics terminal.
The said objects are achieved by means of a device and a method of the invention, and are explained in more detail in the following description, partially with reference to the figures.